Reliability of steel girder bridges with dependent corrosion growth

The conventional approach for evaluating bridge reliability assumes that the resistance or failure of a pair of adjacent steel girders is either fully correlated or independent. The effect of the spatial dependence of corrosion growth on the system reliability of steel girder bridges has not been thoroughly investigated. To fill this knowledge gap, the Gaussian, Gumbel, Clayton, and Frank copulas are used to model the corrosion growth dependence. The reliability estimates of the girder system under these copulas are compared, considering a low, medium, and high degree of dependence. The variable-based power-law model and Gamma process-based model are used to depict the uncertain evolution of corrosion over time. The proposed approach is exemplified using a steel girder system. The analysis results indicate that the difference in reliability estimates, based on the copula selected to model the spatial dependence of corrosion growth, can be non-trivial.